Motor control prior to dynamic braking



Feb. 16, 1954 c4. R. FURIFOY MOTOR-CONTROL PRIOR TO DYNAMIC BRAKINGFiled Jan. 27, 1953 21. PROGRESS HOLD INVENTOR WITNESSES: 47 wd GeorgeR.Purifoy. BY

ATTORNEY Patented Feb. 16, 1954 BRAKING George R. Purifoy, Pittsburgh,Pa., assignor to Westinghouse Electric Corporatiom East Pittsburgh, Pa.,a corporation of Pennsylvania Application January 27, 1953, Serial No.333,546

3 Claims. 1

My invention relates to direct-current elec- 'trically propelledrailway-vehicles, and it has particular relation to'eleotricalcontrol-systems thereof, in which provision is made for dynamic braking.The principal object of my invention is to provide a new means orinstrumentality for reducing the high buildup-rateand'overshooting "ofthe motor-current and the motor-voltage when the dynamic-brakingcircuits are" established while the'motors are bein 'operated at highspeeds. Excessive motor-current and excessive "motor-voltage result notonly in a rough brakeiapplication, but also in motor-flashing. Myinvention is an improvement over the control- "equipment which is shownin a companionap- 'plication of William L. Barclay, Jr., and myself,Serial No. 295,794, filed June 26, 1952, in which "other'means wereprovided for the purpose of mitigating overshooting when dynamic'brakingis "applied.

1 have provided an auxiliary switching-segment or segments on thefield-controller, for-taking care of an objectionable condition whichsometimes occurswhen the motorman elects to operate the car or train,for a while, on either the switching position or the seriesrunning'position of the master controller, with the train running atspeeds much higher'than the normal switching-speeds or the normalseries-running speeds, and subsequently going into dynamic brake "fromeither said switching position or said series running position.

' With the foregoing and other objects in view, my'invention'consists inthe circuits, systems,

apparatus, combinations, parts, and methods of design and operation;hereinafter describedyand illustrated in' the accompanying drawing;- thesingle figure of which is a simplified circuitdiagram'of the-parts ofone car, which are neces- --sary to'illustrate my present invention,-omitting many parts which are known to be needed in a successfulrailway-control equipment of the type to which my invention is applied,but which are not necessary to he discussed in setting forth the natureand operation of my present improvement. The drawing represents some ofthe equipment which is carried by a single electrically propelledrailway-car embodying my invention. 1 Theprincipal novel feature, asshown in the illustrated -form of embodiment of my invention, relates tothe provision of contact-segmentsnfland 253 'onxthe field-controller FC,in addition to the contact-segment 306 which is shown insaid com---panion-application.

Direct-current power is supplied to the car ment, carried by the car.

from a third rail Hi5, or a trolley wire, which is engaged by athird-rail shoe tile, or a trolley pole,

pantograph, or other current-collecting equip- The third-rail shoe 3%energizes a line IS"! which constitutes a supply-circuit for the car.The traction-motors for the car are series motors, which are indicated,

by way of showing a simple example in the'drawing, as'comprising twomotor-armatures Aland A2, each being associatedwith its own series fieldwinding SF! and SP2, respectively, the ordinary reversing-switches beingomitted for thesake of "simplicity. Two'series-motor means, or circuits,

are shown. The first series-motor-means comprises, in series, anarmature-terminal 'AI'l, a motor-armature or armatures Al, anintermediets connection point .AXI, a series field lwinding or windingsSFI, for supplyingthe fieldexcitation for said armature orarmaturesyrand a field-terminal Fll. The corresponding parts for thesecond series motor means are indicated at ATZ AZ, .AIQ, SF2, and FT.

A series-parallelmotor-control arrangement is shown in the drawing-inwhich a line-switch or vrelayLSl and a ground-switch GI are used aspower-switch means for establishing apowercircuit for'energizing themotors, by connecting 1. the first armatureeterminal A'Il to thesupplycircuit I91, and connecting the second armature- J terminal ATZ toground. For completing :the

in addition to the power-switches LSI and'Gl. For parallel-motoroperation, two switches M and series-circuit connections, a switch JRis.closed G are closed in addition to the power-switches LS! and Gt. Theparallel-motor switch M provides a circuit-connection between thearmatureterminal ATI of one series-motor means and the field-terminal FTof the other series-motor means; whilethe other parallel-motor switch Gprovides a circuit-connection between the. other armature-terminal AT2and the other field- .terminal'FHj During an intermediatetransition-period, a switch J is closed. Thesemotorcontrollingconnections are all in accordance with a well-knownswitching-system. Dynamic-braking circuits are established by openingthe two power-switches'LSl and (ii and closing a braking-switch Bl inaddition to the two'parallel-connection switches M and G, alsorangement.

inaccordance with a well-known system or-ar- The braking-switch Blprovides a common dynamic-braking circuit-connection I 98 betweenthe'respective intermediate connectionpoints AX! and AX2 of the twoseries-motor mea.ns, thusproviding two dynamic-braking circuits whereinthe motor-armature or armatures- S of each of said series-motor meansare loaded by the field winding or windings of the other one of saidseries-motor means, respectively.

A progressively operating acceleration-controlling means is provided, inany suitable manner, including a first-operating voltage-controllingmeans for controlling the voltage which is efiective on themotor-armatures AI and A2. In the illustrated form of embodiment, thisvoltagecontrolling means comprises a suitable number of series-connectedaccelerating resistances, as indicated at RI, R2, R3 and R4. Theresistance RI is disposed between the supply-line I91 and the firstarmature terminal ATI, and is shorted out by means of a secondline-switch LS2. The resistance R2 is in series with the firstfield-terminal FI I, and is progressively shorted out by means ofswitch-contacts SI, S3 and S9. The resistance R3 is in series with thesecond fieldterminal FT, and is progressively shorted out byswitch-contacts S2, S4 and Slil. The resistance R4 is in theseries-motor connection which is made by the switch JR, and thisresistance is finally shorted out by the transition-switch J, forobtaining the full-series power-circuit connection of the motors.

During parallel motor operation, the switchcontacts S3, S5 and S9, SIBare successively or progressively closed, during the acceleration of themotor, and after all of the accelerating-resistances R2 and R3 have beencut out, the acceleration-controlling means of my control-apparatusincludes a finally-operating field-controlling means for progressivelyreducing the field-strengths of the motors, to provide shortfieldoperating-conditions.

In accordance with a usual arrangement, the motor-fields are reduced byequipping each of the series field windings SFI and SFZ with afield-shunt, comprising an inductive reactor XI or X2, as the case maybe, and a variable resistor RSI or RS2, respectively. The field-shuntsXI-RSI and X2-RS2 are field connected in parallel relation to theirrespective field-windings SFI and SP2, by means of contact-terminals IIand I2, respectively, of a progressively or sequentially operatingfield-controlling means, which is herein illustrated as an electricallyoperated drum-type field-controller FC. After the respectivefield-shunts have been connected into operation, the field-shuntresistances RSI and RS2 are then progressively shorted out by successivecontroller-points I3, I5, IT and I9, for RSI, and I l, I6, I8 and 20,for RS2, as the fieldcontroller PC is moved from its initial full-fieldposition FF, through its intermediate positions FI, F2, F3 and F4 to itsshort-field position SF,

at which point the field-winding currents are mentionedaccelerating-resistances R2 and R3,

in establishing the complete dynamic-braking circuit. Thebraking-resistance R5 is progressively shorted out by means ofbraking-switches B2, B5 and B6, during dynamic-braking operations, afterwhich the acceleration resistances R2 and R3, or portions thereof, areprogressively shorted out, as by the switch-contacts S3, S4,

and s9, SI I1. (The switch contacts SI and s2 are permanently closedduring the dynamic-braking operations, in the illustrated system.)

The progressive operation of the various resistance-shorting switches,during both motoring operation and dynamic braking, is under theautomatic control of a suitable limit-relay or relays, which areenergized to be responsive to conditions which accompany excessivetorque in the motors. Such a limit-relay is illustrated in the form of acurrent-relay CR, having an actuatingcoil CR which is connected inseries-circuit relation between the connection-point AXZ and thearmature A2. This current-relay CR also has a back-contact I99 (alsomarked CR), which is normally closed, that is, which is closed in thenon-actuated or low-current position of the relay.

The current-relay CR is also provided with certain recalibrating-means.In accordance with previous practice, this relay is provided with acumulatively operating rate-coil RC, which in energized through aweight-responsive rheostat 280, during accelerating operations, andwhich is energized through a braking-responsive rheostat 25H duringdynamic-braking conditions. The weight-responsive rheostat Zilll isautomatically adjusted according to the variable weight or live loadcarried by the car, so that the ratecoil RC is the most strongly excitedduring lightload conditions, thus reducing the minimumcurrent setting atwhich the limit-relay CR picks up and opens its back-contact I99. Thebraking-responsive rheostat 21 is automatically changed in response tothe position of a brakehandle 202, which will be subsequently described,so that the rate-coil RC has its maximum. excitation when a lowbraking-rate is called for, thus providing a low minimum-current settingat which the limit-relay CR picks up and opens its back contact I99, andalso providing limitrelay calibration which is different from brakingand power-operating conditions.

All of the electrically controlled relays and switches which are shownin the drawing are diagrammatically indicated as having verticalswitch-stems (indicated by dotted lines), which are biased by gravitytoward their lowermost positions, and all of these switches and relaysare shown in their deenergized or non-actuated positions. All of therelays and switches are electrically controlled, and they areillustrated as being electrically or magnetically operated, by means ofan appropriately numbered or lettered coil or solenoid, represented by acircle, acting magnetically to lift an armature which is representeddiagrammatically by a smaller circle inside of the coil-circle. Ingeneral, the same switch-designation is applied to any particularswitch, its coil, and its contacts, by way of identification of theparts belonging to a given switch or relay.

The various electrical control-circuits for a train are under thecontrol of a number of trainline wires, which extend from car to car,throughout the entire length of the train (not shown). In the simplifiedcircuit-diagram of the drawing, eight of these train-line wires areused, being given their usual designations, namely (I-) 3, 4. 5, 6, "I,I2 and GS.

Energy for the various relay-circuits or switchcircuits is provided bymeans of a battery B on each car. The negative terminal of each batteryis permanently grounded, while the positive terminal of each battery isconnected,

through a switch 203,120 the positive train-line wire , Each end of eachcar is provided with'a motor.- mans master controller MC, only one ofwhich is indicated in the drawing. The illustrated master controller MCis indicated as being an accelerating-controller having an off-positionand three on-positions 1, 2 and 3. In each of the three on positions ofthe master-controller, MC, the positive control-wire is connected to thetrain-line wires I2, GS" and 6. The trainline wire I2 is theenergizing-wire for the operating coil LS! of the line-switch LSI;'while the train-line wire GS is the energizing-wire for the operatingcoil GI of the ground-switch GI, as will be subsequently described. 7

In'the second and third on-positions of the accelerating-drum of themaster controller MC, the train-line wire 4 is energized from thepositive bus while in the third on-position of this controller, thetrain-line wire I is energized from the positive bus (-1-) In theoff-position of the accelerating drum or master controller MC, aconnection is made from the positive control-wire to the trainline wire3. In the master controller MC, in accordance with a known practice,there is an overlap between the off-position contact which energizesthis conductor 3, and the on-position contactswhich energize theconductors I2 and GS, so that, during the notching-off of themaster-controller MC, the contact at 3 is made before the contacts at I2and GS are broken. This overlapping construction is particularlynecessary in properly controlling a braking-oporation protective-relay'BP, which will be subsequently described, and which also constitutesthe subject matter of a Riley Patent 2,597,183, May 20, 1952.

The first on-position of the accelerating-con- 1 troller MC, in Fig. 1,is a switching position, in which the control-wires I2, GS, and 6 areall energized. The control-wire I2 energizes a control-circuit wire I0,through interlocks which are provided, by the braking-switches BI andB5, in the form of back-contacts 204 and 205, respectively; and thecontrol-circuit wire I0 is used to energize the operating-coil LSI ofthe line-switch LSI.

Inaccordance with a usual practice, the exciting-circuit for theline-switch operating-coil LS! also contains a make-contact 206 of alinerelay LR, which is a voltage-responsive relay which drops out upon avoltage-failure ofthe supply-line 91. This line-relay LR is shown as anundervoltage relay which has an operatingcoil LR which is connectedbetween the supplyline I91 and ground, through a back-contact 201 of theline-switch LS2, said back-contact 20'! being paralleled by amake-contact 208 of the line-relay LR.

As set, forth in an application of R. E. Burkhart and myself, Serial No.269,752, filed February 4, 1952, the control-wire i0 energizes acontrol-wire I20 through. aback-contact'209 of the line-relay LR. Thisline-relay back-contact 209 thus closes in the event of a power-linevoltage-failure, which might result from either a third-rail gap orfrom-any, other cause; and if the master-controller MO is, at the time,on any on-position, the conductors I2 and ID will be energized, andhence the line-relay back-contact 209 will energize the control-wireI20, which I-use as an auxiliary holding-circuit for the protectiverelay-or brakepowerrelay 'BP, which I will subsequently described, inmore detail.

The train-line'wire GS energizes the operating-coil GI of theground-switch GI, through interlocks which are provided by back-contacts2I0', 2H and 2I2, which are carried by the braking-switches BI and B5,and by the parallel-0peration switch (3-, respectively. The back-contact2I2 is paralleled by'a make-contact 2I4 of the ground-switch GI.

The train-line wire 6 is connected, through an LSI make-contact 2 I5, toa relay-circuit" 80, which is connected", through a GI make-contact 2I5,to a circuit 62 which constitutes a holdcircuit for theswitch-progression for the accelerating-resistance short-circuitingswitches SI to SIOand J. This hold-circuit S2 is used toenergize'the'operatingcoil JR of the series-motor circuit switch JR,through interlocks on the switchesJ and G, in the form of back-contacts2 I 'I' and 2-18, respectively.

According'to my present invention, 1 also-inelude; in theenergizing-circuit of the JR-coil, a field-controller contact-segment225, which is closed in the initial, fuli-field position FF of thefield-controller PC, but which is opened when the-field-controller ismoved to its short-field position or say when the field-controller movedfrom its second on-position F2 to its third on-positicn F3. As shown,the new'iield-controller contact-segment 228 is included in a circuitwhich extends between the hold-circuit;62 and a control-circuit G3 whichin turn energizes the operating coil JR of the series-motor-circuitswitch JR through the interlocks 211 and -2I8. The purpose of thiscontact-segment 220 will be subsequently described.

The said hold-circuit 62 is also used to directly energize theclose-coil or actuating-coil BP-Close of the braking-operationprotective-relay BP.

The result of the master-control energization in the No. 1 on-positionof the master-controller MC,'is thus to close the main-circuit orpowercircuit contacts of the traction-motor switches LSI, Gland JR,thereby completing a series-connection motor-circuit for causing a slowmovemerit-of the train, for so-cailed switching purposes, with all'ofthe accelerating-resistances in series with the motors. This circuit canbe traced from the supply-circuit I522, through the main LSI contact,the resistor the armature AI, the series'field SFi, the resistance R2,the resistance R4, the main JR contact, the resistance R3, the seriesfield SP2, th current-re1ay coil OR, the motor armature A2, and the mainGI contact, to ground.

At the same time-the energization of the braking-operationprotective-relay BP paves the way for the subsequent energization of thedynamic- .brakingcircuits of the motors, and also for the automaticprogression-control, under the control of the limit-relay orcurrent-relay CR, both for the motoring progression during acceleration,and for the dynamic-braking progression during an application of thebrake-lever 282, as will be subsequently described.

The hold-circuit 62, which is energized in the No. '1 on-position of themaster-controller, is also connected, through an LSI make-contact 222,to a hold-circuit 6?, which is used in the subsequentprogression-control.

The No. 2 position of the accelerating-controller MC is the first of tworunning-positions 2 and 3. It initiates the accelerating progression ofthe series+motor connections-by energizing the train-line wir 4, whichis connected, through an LSI make-contact 224, to a conductor 40. Theconductor 40 is connected, through an LS2 backcontact 225, to aconductor 42, which energizes the operating-coil LS2 of the secondline-switch LS2, which acts as the first acceleration-progressionswitch, by short-circuiting the first accelerating-resistor RI. This LS2switch has a makecontact 221 which picks up and serves as aholding-circuit contact between the circuits 60- and 42.

If there were any doubt about the adequate speed of closure of theseries-motor-connection switch JR, the energizating-circuit for thefirst resistance-shorting switch LS2 could have included a JR-interlock(not shown in my drawing), to make sure that the JR-switch was closed,before the LSZ-switch is energized, thus avoiding the possibility ofskipping a resistance-reducing step because of the slowness of theJR-switch. as shown, for example, in the companion-application ofBarclay and myself. In my present control-system, as will be more fullydescribed, I provide a progression-system wherein the parallelmotorconnection is sometimes made without progressing through theresistance-reducing sequence of the series-motor connection, but I wantthe LSZ-switch to be closed, and hence I find it mor convenient to makesure that the JR-switch is faster than the first resistance-shuntingswitch LS2, thereby avoiding the necessity for a JR-interlock in theenergizing-circuit for the resistance-shorting switch LS2.

This second line-switch LS2, which serves as the firstresistance-shorting switch, also has a make-contact 228 which connectsthe circuit 40 to a circuit 45. The circuit 45 is connected, through theCR limit-relay back-contact 199, and through a BP make-contact 230, to acircuit 46, which constitutes the main limit-relay progression-circuitof the control-equipment. limit-relay progression-circuit 46 is thus notonly under the control of the limit-relay or currentrelay CR, which isresponsive to excessive motorcurrents, but it is also under the controlof the braking-operation protective-relay BP, which must be closed (withthe protective relay in its actuated position), before there can be anyprogression during either the motoring operation or the brakingoperation.

This limit-relay progression-circuit 46 is cont nected, through an LS!make-contact 23L to a progression-wire 4?, which is connected through anLS2 make-contact 232 to a control-wire 50. Th control-wire 5G energizesthe operating-coil l-2 of a second resistor-shorting progression- Aswitch 1-2, which carries the two main contacts SI and S2, thisenergization being efiected through a back-contact 233 of this sameswitch l-2. Thus, this energizing-circuit from the conductor 50 includesthe switch-out interlock 233, a conductor 5|, and the coil 1-2. Thissecond progression-switch l-Z picks up and closes a holding-circuitmake-contact 234', which energizes the circuit 5! from the hold-circuit61.

The actuation of the second resistance-shorting switch i-2 also closes amake-contact 235, which energizes a circuit 53 from theprogression-circuit 47, through a back-contact 2390f a thirdresistance-shorting switch 3-4, which is the switch which carries themain switchingcontacts S3 and S4. The energizing-circuit for this switchextends from the conductor 53, through the operating-coil 3-4 and aback-contact 23? of a fourth resistance-shorting switch 9-H thencethrough a control-circuit conduc- This 8 tor I09, and a J-switchback-contact 238, to the grounded negative battery-terminal Theactuation of the third resistance-shorting switch 3-4 closes amake-contact 23-9 which establishes a holding-circuit for the conductor53 from the hold-wire 67.

The actuation of the third progression-switch 3-4 also closes amake-contact 24!, which completes a circuit from the progression-wire 41to a conductor 59, which energizes the actuating coil 9-!!! of thefourth resistance-shorting switch S-IB, which carries the mainswitch-contacts S9 and sit, the negative terminal of said coil 9l I)being connected to the previously described wire I09. The actuation ofthis fourth switch 9-) also closes a make-contact 242 which establishesa holding-circuit for the conductor 59 from the hold-wire 61.

The actuation of the fourth resistance-shorting switch 9-!!! also closesa make-contact 243, which is connected between the progression-wire 41and a circuit 55, through a back-contact 244 of the thirdresistance-shorting switch 3-4. This circuit 65 energizes theoperating-coil J of the transition-switch J, through a. G-switch backcontact 245. The transition-switch J then closes its main orpower-circuit contact J, which constitutes the last step in seriesmotor-connection for the traction-motors, cutting out the lastaccelerating-resistance R4. This transition-switch J has a make-contact241 which establishes a holding-circuit from the conductor 65 back tothe hold-line 82. Th previously described J-switch back-contacts 2H and238 are opened, upon the energization of the transition-switch J, thusdropping out the initial series-connection switch JR, and the third andfourth acceleratingswitches 3-4 and 9-H).

The next step in the acceleration of the traction-motors is accomplishedby a movement of the master-controller MC to its No. 3 position, whichis a parallel-motor running-position. This position 3 of themaster-controller energizes the train-line wire I, which is connected,through a. back-contact 249 of the fourth accelerating orresistance-shorting switch 9-36, and a makecontact 250 of thetransition-switch J, so as to energize a control-circuit 3|, which is inturn connected, through a JR back-contact to a parallel-connectioncontrol-circuit 56 which energizes the operating-coils M and G of theparallel-motor-connection switches M and G. These switches M and Gthereupon connect the traction-motors in parallel, between thesupply-circuit l9! and ground, with only the first two of theresistance-shorting switches energized, in the illustrated form ofembodiment of my invention-namely the second line-switch (or firstprogression-switch) LS2, and the second progression-switch i-Z whichcarries the main switchlug-contacts SI and S2. The energization of theparallel-connection switch G opens the previously described back-contact245, which drops out the transition-switch J. The energization of theparallel-connection switch M closes a make-contact 252, whichestablishes a holding-circuit for the conductor 66 from the line '60.

According to my present invention, in addition to the interlock 252 ofthe parallel-connection switch M, I also provide a new field-controllercontact-segment 253, connected in parallel to said M-switch interlock252. This new contactsegment 253 thus connects the relay-circuit to theparallel-connection circuit 66. Said contact-segment is closed wheneverthe acceleraclone-progression of. the traction-mctor control hasadvanced farienoughv (as will be subsequently described) to move thefield-controller to. any position close to its shortefield position 5say to any field-control po: tion bet F3. Th purpose of thisfield-controller contact'segment will be subsequently described.

Responsive to the dro,=; -ping--out of the transition-switch J (whichwas deener a result of the energization of the parallel-connectionswitch M), the back-contact 238' of this tra si" tion-switch recloses,and re-il "'atcs the switchprogression of the resistance-shortingcontacts S3 to Sit, under the control of th "witches 3-- and 9-Hl,through the circuits r 11 have been previously described. Thisestablishes the mash mum armature-voltage conditions on the motors, andit completes the connections for the full-field parallel-connectionoperation of the traction motors.

As soon as resistance-shorting switch B-lE!closes, it closes anadditional contact which energizes a field-controller actuating-circuitfrom the progress-wire 4?, circuit extending from the wire through. thepreviously mentioned make-contact the of the resistanceshorting switch$49, a back-contact 2% of the third progression-switch 34, amake-contact 25! ofthe parallel-connection switch M, and a make-contact258 of the line-switch LS2, thence, to the short-field wire as of thefieldcontroller FC.

The short-field wire 39 of the field-controller FC energizes theshort-field coil FC-SF, or other means which may be used to move thefield-con- 1':

troller from its full-field position F5 to its short field position SF.This starts the progressive operation of the field-controller, and itmay be brought about in any oneof' several ways. In

the illustrated form of embodiment, since the .1

power for the short-field wire 39 is obtained fro .i the progress-wire41, which is under, the control oithe limit-relay CR, the fieldweakening progression. of the field-controller FC progresses under thecontrolof the limit-relay CR, until the short-field position SF isreached. This completes the connections for the short-fieldparallelconnection operation of the traction-motors, thus completing theaccelerati0n-progression If, now, the master-controller MO is returnedto its off-position, the car or train, being now running at someconsiderable speed, the master,- controller will energize the train-linewire 3, which may be described as the brakeewire 3, be.-

cause it is used to set up thedynamic-braking circuits for the motorsduring the coasting operation. When the braking-prctective relay BP isused, shown, the brakeewire 3 is also used,.,to directly energize ahold-coil BP-Hold of the brake ing-protective relay BP, and thishold-coil may be hold the relay actuated or closed, once it has beenactuate As set forth in the previously mentionedapplication Burlthartand myself, the BP-l-Iold coil is also provided witha,secondenergizingcircuit, which is independent oi the brake-wire 3, and

Cal

thus-operative in any of the three on-positions of the master-controllerMC. This second hold-coil energizing-circuit includes a make-contact 259of this brake-protective relay BP, and this makecontact 259' is used toenergize the brake-wire 3 from the previously described control-circuit20, which is under the control of the line-relay LR, so that thecontrol-circuit i2ii is energized whenever, there is afailure of the,line-voltage, at a time. when the train-line wire 52' is energized, thatis, at a time when the master-controller is on any one of its threeon-positions, as previously described. In this way, I not only maintainthe e-nergization of the BP-Hold coil under. theno-voltage conditionsjust described, thus making sure that the brake-protective relay remainsin its actuated condition, but I also immediately energize thebrake-line 3, without waiting for the master-controller MC to bereturned. to. itsoff-position, which establishes the coastingbraking-circuit connections, as will now be described.

The brake-wire 3is connected, through an LSI back-contact 269 and a BPmake-contact 26!, to a control-circuit 313. This control-circuit 3IBisconnected, through a GI back-contact 262, to the previously describedcontrol-circuit wire 3!, which energizes the previously describedparallelmotoring switches M and G through the JR backcontact 25! and thecontrol-wire G6. The controlrconductor (HE is also connected, through aG! back-contact 253,1:0 a control-wire BIG, and thence to the positiveterminal of the brakingswitch coilBl, the negative terminal of which isconnected in a circuit which includes a B5 back-contact 265, a conductorI92, another B5 hack-contact 2'65, a conductor I04, and a JRheroin-contact 2'57, and thence to the grounded negativebattery-terminal The closure of the switches M, G and BI completes theestablishment of a weak coasting-operation dynamicorakingcircuit-connection for the traction-motors, with all of the availabledynamic-braking resistances R5, R2 and R3 in circuit, thisdynamic-braking resistance being large enough so that the brakingtractive-effort is usually quite wealr, at moderate motor-speeds, thuspermitting the train to coast, with litle or no sensible or perceptiblebraking-effect, as long as the field-controller FC remains in itsshort-field position.

A connection is also provided, for controlling the field-controller FCduring the coasting-operation. In accordance with a known practice, Iprovide a circuit extending from the controlwire 316, through aback-contact 258 of a brakerelay BR, to a control-circuit 32, and thencethrough the back-contact 269 of a spotting-relay SE, to the full-field.wire 33 of the field-controller FC. The brake-relay BR. was shown anddescribed in a Riley-Purifoy Patent 2,523,143, granted September 19,1950. The spotting relay SR is a previously used relay, having anoperating-coil SR which is included in the common brake-circuitconnection I98, so that this relay responsive to the braking-circuitcurrent. This spotting-relay SR is adjusted to have a low-currentpickup-value, so that it can hold the braking-circuit current to a smallvalue suitable for spotting purposes, during the coasting operation ofthe traction-motors, as is well understood in the art.

The full-field wire 33 of the field-controller FC energizes a full-fieldcoil FC-FF, or other means for causing the field controller FC to moveor progress from, its short-field position SF to its ,i ii full-fieldposition FF. This enerfiization of the full-field coil FC-FF under thecontrol of the spotting relay SR thus progressively adjusts thefield-controlling means FC toward its full-field position, asspotting-conditions may require.

In accordance with a known control-method, the spotting-relay SR has amake-contact 210 which connects the circuit 32 to a circuit 36, whichgoes to a field-controller contact-segment 21!, which is closed onlyduring certain early points in the progressive movement of thefieldcontroller FC from its full-field position FF toward itsshort-field position SF. This field-com troller segment 21! ispreferably opened at a certain point near the short-field-position SF,preferably before the field-controller reaches this short-field positionSF. As shown, I prefer to have this field-controller segment 2''! closedat the positions FF through F3 of the field-controller FC. Thisfield-controller segment 2'" is used to connect the wire 36 to theshortfield wire 39 of the field-controller FC. In this way, when thespotting current is too large, that is, large enough to pick up thespotting-relay SR, the spotting current is reduced by adjusting themotor-fields toward a weaker condition, by making the field-controllerFC progress in the direction towards its short-field position, but thisprogression is usually arrested before the fieldcontroller returns allof the way back to its original short-field position SF, which itoccupied before the spotting-control commenced to operate.

A service braking-application is made by the closure of the brake-lever202, which energizes the full-brake wire from the brake-wire 3. Thisfull-brake wire 5 is connected directly to the coil BR of thebrake-relay BR. The brake-relay BR has a make-contact 272, whichconnects the fullbrake line 5 to the conductor 35 which leads up to thelimit-relay progression-circuit 4'5, thus putting the brakingprogression under the control of the back-contact I99 of the limit-relayor current-relay CR, as well as under the control of the BP make-contact238, both of which are in circuit between the conductor c5 and thelimit-relay progression-circuit 46. At the same time, the opening of theback-contact 268 of the now-actuated brake-relay BR takes the brakingprogression out of the control of the spotting relay SR.

Whenever a braking-application is called for, the energization of thebrake-relay BR closes a BR make contact 213, which is used in theinitiation of the dynamic-braking progression. Thus, the BR make-contact273 is used to make a connection from the limit-relayprogression-circuit 46 to the full-field wire 33 of the field-controllerPC. This causes a progression of the field-controller FC until itreaches its full-field position FF, under the control of the limit-relayCR.

The closure of the brake-relay BR also closes a make-contact 214 whichmakes a connection from the control-wire 3 IC to a braking-operationhold-wire H, in readiness for use in the subsequent brake-progressionoperations. When the braking-controlling progression has proceeded tothe point at which full-field conditions are restored in thetraction-motors, the field controller FC closes a full-fieldcontactmember 216, which closes a circuit from the fullfield wire 33 toa conductor 49, and thence through a BR make-contact 211 to abrakingprogression circuit 48.

The energization of the braking-circuit progression-wire 48 immediatelyserves, through a Bl make-contact 218, which is already closed, toenergize a circuit 12, which is connected, through a B2 back-contact219, to a circuit 82 which is connected to the positive terminal of theB2 actuating-coil, the negative terminal of which is connected to thepreviously described conductor 192. The B2 switch thus picks up andcloses its main contact B2 which shorts out a part of thebraking-resistance R5 in the common dynamicbraking circuit Hit of thetraction-motors. The actuation of the B2 switch also closes amakecontact 280 which establishes a holding-circuit for the wire 82 fromthe hold-wire H.

A circuit is next established from the lower end of the progression-wire48, through a B6 back-contact 28E, to a conductor 15, and thence througha B2 maize-contact 282, which has just been closed, to a conductor 85which is connected to the positive terminal of the B5 actuating-coil,the negative terminal of which is connected to the previously mentionedwire Hi l. The B5 switch closes its main-circuit contact B5, whichshorts out more of the braking-resistance R5 in the commondynamic-braking circuit 93 of the traction-motors. At the same time, theB5 switch closes a make-contact 233 which establishes a holding-circuitfrom the conductor 85 back to the hold-wire H.

The energization of the braking-progression switch B5 opens itspreviously mentioned backcontacts 265 and 265, thus dropping out theswitches Bi and B2, the main contacts of which are both short-circuited,now, by the main contact B5. The dropping-out of the Bi switch closesits lowermost back-contact 285, which completes a circuit from theconductor 15 to a B5 make-contact 285, and thence to a wire 86, which isconnected to the positive terminal of the B6 coil, the negative terminalof which is connected to the wire NM. The B6 switch thus closes, andcloses its main contact B6 which further shorts out some of thebraking-resistor R5, thus still further reducing the efiectivebrakingresistance in the dynamic-braking circuits. At

'. the same time, the actuation of the B6 switch closes its make-contact286, which establishes a holding-circuit for the wire 86 from the wireH.

The actuation of the B6 switch also closes a make-contact 287, whichconnects the progression-wire 48 to the previously described conductor12, thereby reenergizing the B2 switch, the negative circuit of which isnow completed from the wire m2, through a B6 make-contact 288, to thewire HM.

It will be understood that all of these brakingprogression operationsare under the control of the limit-relay progression-circuit 45, whichinterrupts the progression whenever an excessive motor-current causes anopening of the current-relay back-contact i953, which is connected inthe energizing circuit for said wire 46, thus interrupting theprogression until the motorcurrent subsides to a desirable value.

The braking-circuit progression-wire 48 is also connected, through a G!out-contact or back-contact 2%, to the accelerating-resistanceprogression-wire M.

After the second closure or actuation of the B2 switch, so that the B2and B5 switches are now both closed, a circuit is made, from theaccelerating-resistance progression-wire 41, through a B2 make-contact290 and a B6 makecontact 2!, to the previously described conductor 50,thus re-initiating the progression of thaswitchesl-2,, 34-4, and: 9-40,which pro:-- ressiviely I close the accelerating resistor switches.

SI, to Sit, thereby cutting out the accelerating resistors R2 and R3which are in the individual portions of the respective dynaniic-brakingcircuitsofthe traction-motors, this progression being;alsounderthe-saine limit-relay control.

Ever since the actuation. of the B5 switch, a B5; make-contact 2221 hasbeen energizing the accelerating-resistance hold circuit '15? from thebraking-operation,hold-wire."H, in readiness for this progression. ofthe accelerating-resistor switchesrsl to S10. Thebraking-progressionthus continues until: substantially all of the brakingresistance.isremoved from the dynamic-braking circuit,.th1ts resulting in theoonipletionoithe dynamic-braking operation, during which: train has beenreduced.

the speed; of the: car or from the initial speed which the dynamichrakewas applied, down to a low speed at which the; dynamic brake fadesout.

If, a braking-operation is to be discontinued, after once having beenstarted; the braking circuit switches are released by an opening ofbrakerhandle 2622, without requiring the establishment of a (perhapsmomentary) power-sir cult (or lVl'C ell-position), in order to deenerthe-braking hold-wire ii. This is accomplishw by the BR-contact 2H,which is in series with the hold-wire. 'll.. Theopening of the brakehandle ZDZ'deenergiZes the brake-relay 13R opens itscontact 2%, withoutrequiring an onposition of the master controller MC to releasethebrake-wirej, in order to deenergise theconduotor 3iC and hencethehold-wire ll.

It has long been customary to antoniaticah 1y adjust the calibration orsetting of limitrelay CR, in.order. to cause, this relay to drop out, inresponsetovarious, accurately controlled desirable minimum motor-currentvalues, during bothv the acceleration-pregression the dynamic-brakingprogression. This is conven iently done by various controls for theenergization of the rate-coil RC of the limit-relay CR. In the drawing,I have shown two known circuits for the. rate-coil control orcalibration. Cne

such rate-coil circuit involves the weight-re sponsive rheostat 2.90,and is traceable from the positive.controlepower line through an LS2make-contact 2513, the aforesaid weight-respon sive rheostat 2%, aresistance 2%, a conductor 92,.aresistance 29,5, andthe rate-coil wire95. A, second old. or known rate-coil energizing circuit, involves thebraking-responsive resistance 2t], and is, traceable from the positivebus through a BR maize-contact 296, and the.

aforesaid brakingqesponsive rheostat 2M to the conductor 92.

As, described" in, the companion-applioation of.

6, which controlsthe switching-operation of the traction-motors, to thetrain-line wire 4, W1 ch controls the progressive series-motor runniuconnections; I

The operation of the simplified. illustrated. ap 7 paratus willibeclear-from the-{running comments which; have-,been. made duringtheprogress or the description, as well as. from the prior. art..

A. few. wordsof added explanation, as tothe features which are moreparticularly related to mynovel controlrcircuit parts, may, however, behelpful.

In accordance with. my. present invention, I. havein efiect nullifiedthe switching-connection.

and the scries-motor connection of the traction motors, whenever theshuntedefield connections I. prevent the, rough-brake conditions whichhave sometimes; been encountered as a result of the motormans.

are established. In this way,

misuse of his master-controller MC. Sometimes, when thecar or train isrunning at high.

speed, with the motors in their short-field con.-

then immediately again moves the master controller MC to itsswitching-position, or No. 1. position, which is not a running-position,and.

not intended to be used except for slow-speed operations while the caror train is being switched;

from track to track.

Nevertheless, motormen sometimes leavev the. master-controller MC inthis switching-position.

while the car or train isrunning at a high speed, and-while the motormanis makingv up his mind whether he wants to resume full running condi:tions, with a iull-power applicatiomor whether he is going to have toinitiate a dynamic-braking. operation. Meanwhile, in previousmotor-control systems the traction-motors are connected across thepower-supply line in their series motor-connections, and the motorfields are very weak;

If, now, the motorman should go into a dy-- namicbraking operation, withthe motor-fields in an, excessively weakened condition for. thatparticular. motor-speed, then the dynamic-braking operation would startwith the motors having.

a. very low field-flux. This low-flux. condition would be doubly.aggravated, not only on account. of.the presence of the field-shuntsXIRS| and. X2-RS2, which divertv a considerable part of.

whatlittle motor-current there, has been, im-.-

mediately prior to. the establishmentof thedymanna-braking connections,but the motoring-' currents themselves had beenexcessively small,because. the. motorman had beenerroneously op erating, at.a.high speed,on his. No.,1. switchingposition, which means thatall of theaccelerating resistances RLRZ, R3v and. R4 had been in,

themotor-cirouits, so that very little motor-currentcouldbefiowing, thatis,.prior to our intro.-

duction of the new. neldecontroller contactrseg:

rcent Thus, when. dynamicebraking connections are established, while.the. motor-flux was, so extremely weak, and-remembering that themotors.

have aiather slow time-constant, so that their motor-flux cannot bebuilt up anything like as. rapidly as the progressionnate during thebuild up. of. dynamimbraking conditions, thenthe dynamicbraking,currents will at firstbe extreme- 1y low, causing thedynamic-braking progression to proceed. at its maximum rate, withoutintere ruption by thepiclzing-up of. the limit relay CR,, sov that, whenthe motor-flux finally builds up.

to its. increased valuatoo muchresistance will have beencutout of thedynamic-braking cir cults. and. excessive dynamimbrakingcurrents willbezobtained'.

I avoid these difiiculties by, in effect, preventing the motorman fromoperating a fast-moving car or train with the traction-motors connectedin either their switching-connections or their series motor-connections.Whenever the acceleration-progression of the traction-motor control hasadvanced far enough to cause the fieldcontroller FC to adjust itself toany of its positions F3 to SF, if the motorman should then move hismaster-controller MC to its off-position, and should then immediatelynotch it up again to its No. 1 switching-position, while the train isstill running fast, the field-controller contact 306 will connect theswitching-controlling wire 6 to the wire 4, and my new field-controllercontact 253 will continue this connection on, to the parallelmotorcontrol-wire 66, through the circuit 62l -68--25366. At the same time,my new field-controller contact 220 prevents the energization of theseries-motor-connection switch JR from the circuit t2 i 560--2 I5-62--220-63.

Consequently, neither the series-motor switching-connections nor theseries-motor runningconnections are made, under these conditions, by theNo. 1 switching-position of the master-controller MC; and theswitching-connection trainline wire 4 is connected straight on, to theparallel-connection wire 66, which energizes the parallel-connectionswitches M and G, which establish the parallel motor-connections, Thesecond line-switch LS2 is picked up through the circuit 4-2244622542,and this switch LS2 thereupon closes its contact 228 and thus energizesthe progression-controlling circuit 4,224- 453-228-45-l99-430-46-23I-4!.The progress-wire d! rapidly and uninterruptedly cuts out allmotor-resistance during these high-speed parallel-motor-connectionoperating-conditions, thus materially increasing the field-strength ofthe motors, even though the motorman should improperly leave hismaster-controller on its No.

1 switching-position while the car or train is operating so fast.

An advantage of establishing a parallel-motor connection of thetraction-motors, with all of the accelerating resistance cut out,instead of permitting the motorman to operate the train on theseries-motor connection, with the accelerat-' ing-resistance either inor out, while the train is running at speeds high enough to have causedthe field-controller FC to have adjusted itself to.

a shortened-field position, is that the parallelmotor connection causesthe motors to draw enough currentto build up the field-flux to areasonably high value. Thus, if the motorman goes into dynamic brakingfrom this operatingcondition, the motor-field is reasonably high,

and this permits the recapturing of a higher residual voltage, whendynamic brake is applied, then was the case in previous control-systems.'Ifhe dynamic-braking operation therefore starts out with highervoltages generated in the traction-motors, so that the recalibratedlimit relay CR; does not immediately cut out too much braking-circuitresistance in an efiort to bring up of the motor, and this results inprotection against motor-flashing and rough brake-buildup.

While I have described my invention in con-- nection with a motormansmanipulation of the master controller after he has attained highspeedoperating conditions, the same advantages hold true in regard to theprotection of the motors in passing third-rail gaps.

It will be understood, of course, that if the motorman had left hismaster-controller in the off-position, for even a very brief moment,before going into dynamic braking, the coasting or spotting conditionswould have been established, wherein the motors would be connected inparallel, and the motor field-strengths would have been properlymaintained and adjusted by the mild dynamic-braking currents which flowduring coasting or spotting. The trouble came, in previous motor-controlsystems, when the motorman went into the maximum-resistance se--ries-motor switching-connection while the car was running fast, and thenimmediately changed into the dynamic-braking connection for abrakeoperation.

While I have described my invention, and explained its manner ofoperation, in connection with a particular simplified illustrative formof embodiment, I wish it to be understood that the efficacy of theinvention would not be affected by the addition of desired additionalfeatures or safeguards or by the omission of undesired or unnecessaryfeatures, or by the substitution of equivalent or alternative forms ofvarious means or elements for performing the essential elementfunctionswhich have been described and explained.

I claim as my invention:

1. A motor-controlling assembly, including the combination, with aplurality of series motors to be controlled, each series motor includinga motor-armature and a series field winding connected in seriestherewith, of: (a) an accelerating-controller, having an off-positionand a plurality of on-positions, said on-positions including aseries-motor-connection running-position, and aparallel-motor-connection running-position; (1)) a series-connectioncontrol-means, for establishing a power-circuit for energizing theseries motors in a series-motor connection in response to theseries-motor-connection runningposition of said accelerating-controller;(c) a parallel-connection control-means, for establishing apower-circuit for energizing the series motors in a parallel-motorconnection in response to the parallel-motor-connection runningpositionof said accelerating-controller; (d) a variable field-controlling means,for progressively adjusting said series field Winding toward afull-field condition and toward a short-field con-.

dition, respectively; (e) a progressively operatingacceleration-controlling means, for controlling the acceleration of theseries-motor means;

during each of the power-circuit operating-conditions, saidacceleration-controlling means including a first-operatingvoltage-controlling means for controlling the voltage which is effectiveon the motor-armature, and a finally operating field-controlling meansfor causing said field-controlling means to progressively adjust saidseries field winding toward its short-field condition in theparallel-motor power-circuit.

connection; and (f) a shortened-field-responsive means, responsive to ashortened-field condition of said field-controlling means, and responsive' to all of the on-positi'on's of the accelcrating-controller,for establishing the parallelmotor power-circuit connection andnullifying all accelerating-controller on-positions other than theparallel-motor-connection running-position.

2. A motor-controlling assembly, including the combination, with aplurality of series motors to be controlled, each series motor includinga motor-armature and a series field winding connected in seriestherewith; of (a) a supplycircuit for the series motors; (b) apower-switch means, for establishing a power-circuit for energizing theseries motors, first in a seriesmotor connection, and then in aparallehmotor connection, from the supply-circuit; (c) a braking-switchmeans, for establishing a dynamicbraking circuit for the series motors;(d) a variable field-controlling means, for progressively adjusting saidseries field winding toward a fullfield condition and toward ashort-field condi tion, respectively; (e) a progressively operatingacceleration-controlling means, for controlling the acceleration of theseries-motor means during each of the power-circuit operatingconditions, said acceleration-controlling means including afirst-operating voltage-controlling means for controlling the voltagewhich is eiiective on the motor-armatures, and a finallyoperatingfield-controlling means for causing said field-controlling means toprogressively adjust said series field winding toward its shortfieldcondition in the parallel-motor powercircuit connection; (f) aprogressively operating spotting-controlling means for controlling thespotting-adjustment of the dynamic-braking circuit during coastingconditions, said spottingcontrolling means including a mean for causingsaid field-controlling means to progressively adjust said series fieldwinding toward its full-field condition; (y) a progressively operatingbrakingcontrolling means, for controlling the brakingadjustment of thedynamic-braking circuit during dynamic-braking conditions, saidbrakingcontrolling means including a first-operating means for causingsaid field-controlling means to adjust said series field winding to itsfull-field condition; (h) an accelerating-controller, having anoff-position, a switching-position, a seriesmotor-connectionrunning-position, and a parallel-motor-connection running-position; (2')a bralzing-controllen having an calf-position and an on-position orpositions; (7') a starting-circnit means, for closing the power-switchmeans in a series-motor connection, while maintaining said progressivelyoperating acceleration-controlling means in its lowest-speed condition,in response to a switching-position of the acoeleratingcontroller; (is)an accelerating-circuit means, responsive to a closed condition of t -epowerswitch means, and each of the running-positions of theaccelerating-contro1ler, for causing a progressing operation of theprogressively operating acceleration-controlling means; (2) aspotting-circuit means, responsive to an oiiposition of theaccelerating-controll r and an off-position of the braking-controller,for closing the braking-switch means and causing a progressing operationof the spotting-controlling means; (m) a braking-circuit means,responsive to an elf-position of the accelcrating-controller and anon-position or positions of the brakingcontroller, for causing saidfield-controlling means to adjust said series field winding toward afuller field; and a means, operative after fullfield conditions havebeen established during dynamic-braking conditions, for causing acontinuing progressive operation of the progressively operatingbraking-controlling means; and (a) a means, responsive to ashortened-field con dition of said field-controlling means, forestablishing a temporary circuit-connection between theswitching-position and the parallel-motorcon ection running-position ofthe acceleratingcontroller.

3. The invention as defined in claim 2, characterized by saidshortenedfield-responsive temporary-circuit connection-means (n)including an accelerating-circuit means for causing a progressiveoperation of the first-operating means of said acceleration-controllingmeans (e).

GEORGE R. PURIFOY.

No references cited.

